﻿/************************************************************************

   Extended WPF Toolkit

   Copyright (C) 2010-2012 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license 

   This program can be provided to you by Xceed Software Inc. under a
   proprietary commercial license agreement for use in non-Open Source
   projects. The commercial version of Extended WPF Toolkit also includes
   priority technical support, commercial updates, and many additional 
   useful WPF controls if you license Xceed Business Suite for WPF.

   Visit http://xceed.com and follow @datagrid on Twitter.

  **********************************************************************/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Windows.Media;
using Twi.COMMON.WPF.CtlExtended.Primitives;

namespace Twi.COMMON.WPF.CtlExtended.Core.Utilities
{
  static class ColorUtilities
  {
    public static readonly Dictionary<string, Color> KnownColors = GetKnownColors();

    public static string GetColorName( this Color color )
    {
      string colorName = KnownColors.Where( kvp => kvp.Value.Equals( color ) ).Select( kvp => kvp.Key ).FirstOrDefault();

      if( String.IsNullOrEmpty( colorName ) )
        colorName = color.ToString();

      return colorName;
    }

    private static Dictionary<string, Color> GetKnownColors()
    {
      var colorProperties = typeof( Colors ).GetProperties( BindingFlags.Static | BindingFlags.Public );
      return colorProperties.ToDictionary( p => p.Name, p => ( Color )p.GetValue( null, null ) );
    }

    /// <summary>
    /// Converts an RGB color to an HSV color.
    /// </summary>
    /// <param name="r"></param>
    /// <param name="b"></param>
    /// <param name="g"></param>
    /// <returns></returns>
    public static HsvColor ConvertRgbToHsv( int r, int b, int g )
    {
      double delta, min;
      double h = 0, s, v;

      min = Math.Min( Math.Min( r, g ), b );
      v = Math.Max( Math.Max( r, g ), b );
      delta = v - min;

      if( v == 0.0 )
      {
        s = 0;
      }
      else
        s = delta / v;

      if( s == 0 )
        h = 0.0;

      else
      {
        if( r == v )
          h = ( g - b ) / delta;
        else if( g == v )
          h = 2 + ( b - r ) / delta;
        else if( b == v )
          h = 4 + ( r - g ) / delta;

        h *= 60;
        if( h < 0.0 )
          h = h + 360;

      }

      return new HsvColor
      {
        H = h,
        S = s,
        V = v / 255
      };
    }

    /// <summary>
    ///  Converts an HSV color to an RGB color.
    /// </summary>
    /// <param name="h"></param>
    /// <param name="s"></param>
    /// <param name="v"></param>
    /// <returns></returns>
    public static Color ConvertHsvToRgb( double h, double s, double v )
    {
      double r = 0, g = 0, b = 0;

      if( s == 0 )
      {
        r = v;
        g = v;
        b = v;
      }
      else
      {
        int i;
        double f, p, q, t;

        if( h == 360 )
          h = 0;
        else
          h = h / 60;

        i = ( int )Math.Truncate( h );
        f = h - i;

        p = v * ( 1.0 - s );
        q = v * ( 1.0 - ( s * f ) );
        t = v * ( 1.0 - ( s * ( 1.0 - f ) ) );

        switch( i )
        {
          case 0:
            {
              r = v;
              g = t;
              b = p;
              break;
            }
          case 1:
            {
              r = q;
              g = v;
              b = p;
              break;
            }
          case 2:
            {
              r = p;
              g = v;
              b = t;
              break;
            }
          case 3:
            {
              r = p;
              g = q;
              b = v;
              break;
            }
          case 4:
            {
              r = t;
              g = p;
              b = v;
              break;
            }
          default:
            {
              r = v;
              g = p;
              b = q;
              break;
            }
        }

      }

      return Color.FromArgb( 255, ( byte )( r * 255 ), ( byte )( g * 255 ), ( byte )( b * 255 ) );
    }

    /// <summary>
    /// Generates a list of colors with hues ranging from 0 360 and a saturation and value of 1. 
    /// </summary>
    /// <returns></returns>
    public static List<Color> GenerateHsvSpectrum()
    {
      List<Color> colorsList = new List<Color>( 8 );

      for( int i = 0; i < 29; i++ )
      {
        colorsList.Add( ColorUtilities.ConvertHsvToRgb( i * 12, 1, 1 ) );
      }

      colorsList.Add( ColorUtilities.ConvertHsvToRgb( 0, 1, 1 ) );

      return colorsList;
    }
  }
}
